>
> >Jim seems to be suggesting that it is building up to a toxic dose. Randy
> is denying it. Are different things meant here?


I'm getting pretty  sick of hearing the "denial" claim, or the labeling of
posters as taking black or white positions.  Or as being "pro neonic."  Any
insecticide is by definition a toxin to insects.  Thus, there is some
degree of toxicity from any dose, no matter how small.  Neither I nor
anyone else would deny that.

What we are concerned with then is the degree of adverse effects.  EPA uses
the term NOAEL--"no observable adverse effects level."

The key word here is "observable," which to the regulators, means
"measurable."  Measurable means via data on mortality, learning ability,
resistance to pathogens, behavioral problems, etc.

What this tedious discussion revolves around is the state of science on
measuring these adverse effects.  Researchers keep getting better at
figuring out ways to demonstrate them.

There is no food product that we eat that someone couldn't find adverse
effects from if they look hard enough.  But most of us grounded in real
life simply look at the overall effect on the health of the organism.  Many
of us drink coffee and alcohol, consume salt and sugar, and breathe
polluted air.  Yet the population of humans that do so currently live
longer and healthier lives than any generation in history.

So what researchers look for are groups of people that have a greater
degree of exposure to one or more potential toxicants, in order to see
whether the toxic effect is measurable in overall health and survival.

This is absurdly simple to do with honey bees.  Simply start identical
colonies, and expose them to two different treatments--say continuous
exposure to neonic-treated canola vs untreated canola.  Then measure colony
population and honey production over time, and winter survival.

These three measures reflect reflect the overall calculus of all adverse
effects, and are easy to measure.  To date,  every such sort of trial (that
I'm aware of), in any country, has failed to find measurable overall
negative effects from field exposure.  This doesn't mean that there aren't
toxic effects, but just that they aren't enough to make a difference that
we can see.  Thus, it would be difficult for any objective observer to
become as impassioned about blaming honey bee problems on neonic seed
treatments as some do.

On the other hand, there are clear and measurable adverse effects from
planting dust, chemigation, and some foliar applications.  And measurable
adverse effects from seed-treated crops on bumblebees and likely solitary
bees.  And there is suggestive evidence that there may be effects upon
queens.

All the above are cause for concern.  But that is no excuse for some of the
imaginative interpretations of research recently posted to the List.  Nor
for the contentiousness of the "discussion."  Some of us aren't interested
in winning arguments, but rather in discussing the implications of research
findings.

A problem with the "discussion" of neonics on this List is that it tends to
only come from one side, which means no meaningful discussion.
Unfortunately, any  of us who attempt to keep the discussion objective and
grounded in evidence immediately get labeled as being "neonic defenders."
 This is getting pretty old, and I'm tired of it.  This topic has gone far
from science, and has degraded into personal attacks.

If anyone is truly interested in objective discussion, we can try it off
List.

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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